Biology and population growth of four common stored grain pests on wheat

Abstract

Wheat is a major source of essential nutrients in the human diet. The common insect pests that cause the most damage to wheat during storage include the polyphagous stored grain pests Sitophilus oryzae, Callosobruchus chinensis, Tribolium castaneum and Sitotroga cerealella. Life table studies of these pests were conducted on wheat (CV- PBW-343). The phytoconstituents present in wheat, which were also profiled, led to differences in population growth among the pests. The immature period was longest in T. castaneum, followed by S. cerealella, S. oryzae and C. chinensis. In contrast, S. oryzae greatly outlived the other three in terms of adult longevity. Population parameters, such as potential fecundity, gross reproductive rate and net reproductive rate, were highest in S. oryzae. Meanwhile, the intrinsic rate of increase, generation survival and population growth rate were highest in C. chinensis. These parameters were observed to be lowest in either T. castaneum or S. cerealella. The susceptibility of the wheat cultivar was found to be in the order of S. oryzae > C. chinensis > S. cerealella > T. castaneum. However, none of the tested pests completely dominated the population parameters. These findings help in modifying host metabolite profiles to improve resistance to SGPs.